A universal serial bus (USB) interface circuit, a USB interface implementation method, and a device. The USB interface implementation method comprises: utilizing a difference between a VBUS voltage of an external USB device and a VBUS voltage of an external USB host to identify that a USB interface is connected to a USB host or a USB device, and processing, according to whether the USB interface is connected to a USB host or a USB device, signals on a signal line D+ and/or a signal line D-. Also provided is a computer storage medium.